Tomorrow marks the six-month anniversary of the Affordable Care Act—the landmark legislation President Obama signed last March to ensure all Americans enjoy affordable, high-quality health coverage. We celebrate this anniversary because of the lasting benefits now beginning to take hold and the even greater gains to come over the next 10 years.

The clear need for the Affordable Care Act was driven home anew last week with the release of the 2009 Census data on health insurance coverage, poverty, and income. The numbers delivered a stark reminder of how important this legislation is. In the midst of the Great Recession, 50.7 million people went without health insurance—without the financial security and access to health care services that health insurance provides. More than 4 million more Americans went without health insurance compared to 2008—a dramatic change in a single year that demonstrates just how fragile our health care system is.

In many cases, Americans lost coverage as they lost their jobs—and the employer-sponsored coverage that accompanied those jobs. Sometimes, these individuals, or more likely their family members, were able to obtain coverage through Medicaid, which offers safety-net coverage to some low-income individuals. Other times, though, workers did not qualify, or could not afford to maintain their employer-based coverage through COBRA, the federal program that enables workers to continue to pay for health insurance. Nor could many of them access coverage in the individual market, where the cost of insurance is high, the coverage is mostly inadequate, and insurance companies can pick and choose who they cover.

In the long run—that is, beginning in 2014—the Affordable Care Act will protect American families from this kind of catastrophe. Expanded Medicaid coverage and income-based help with the costs of private insurance will enable low- and middle-income families to have access to affordable, comprehensive health insurance. And they will be able to purchase this coverage without worrying about pre-existing conditions or loopholes in their insurance policies because the Affordable Care Act also reforms health insurers’ discriminatory practices. The new law also creates new health insurance exchanges where consumers can shop for high-value coverage. In the end, 32 million people will gain health coverage. But this six-month anniversary also marks important first steps toward these larger changes. The Department of Health and Human Services has already:

Created a new coverage option for people with pre-existing conditions

Implemented a reinsurance program for companies that provide health coverage to their retirees

Mailed more than 1 million rebate checks to Medicare enrollees with high drug costs

Now, families with sick children know their children are guaranteed health insurance coverage in spite of their pre-existing conditions. Individuals with high health care costs know they won’t be bankrupted by absurdly low annual and lifetime limits on their benefits. Families with young, uninsured workers can cover these young adults through their parents’ policies until they are 26 years old. And no one who has purchased coverage needs to worry that an insurance company can cancel their policy under false pretenses as soon as they get sick.

These early steps don’t fix all of the problems in our health insurance system, but they address some of the most egregious ones.

In the months to come, the tempo of health reform implementation will speed up and the tangible benefits will become even more apparent. Specifically, in 2011:

Medicare beneficiaries with very high drug costs will save more than $1,500 as the dreaded “doughnut hole” in their prescription drug benefit closes.

States will have greater financial incentives to provide long-term services and supports at home, where elders and people with disabilities prefer to live, rather than in nursing homes.

Medicare and Medicaid will begin using their payment systems to induce quality improvements in the delivery system, for example by reducing hospital payments when a patient suffers from a hospital-acquired infection, and by rewarding doctors and other providers who do a good job of managing patients with complex conditions.

These reforms and others to be implemented over time will secure important new health care benefits for millions of Americans, insured and uninsured alike, setting the stage for the major reforms to come in 2014 and beyond.

In the weeks to come, though, we will hear a lot of rhetoric from the opponents of health reform. They will call for repealing the new law and either reverting to the old status quo or starting health reform over from scratch. Reverting to the unaffordable health system in place before this landmark reform would leave millions of Americans uninsured, while ignoring the unsustainable growth of health care costs.

But repealing only parts of the Affordable Care Act would carry a heavy price, too. One recent analysis notes that repealing the requirement that all individuals carry health insurance and the subsidies that help individuals and families afford this coverage would cause health insurance to cost twice as much in 2019 as it will under the Affordable Care Act.

We have made so much progress since the passage of the Affordable Care Act on March 23. And there is more to come. As the implementation of all the pieces of health reform unfolds, we will see our fragile health care system gain new vibrancy and strength. Millions of Americans will gain the health coverage and financial security they deserve.

Karen Davenport is the Director of Health Policy at the Center for American Progress. To read more of our analysis and recommendations for health care reform, go to the Health Care page of our website.